One of the challenge of deploying PIA is that you need to include dlls from the libraries you used, such as Office 2007 PIA Redist.

COM Interop Assemblies deployment can also be complex and they do not support multiple host versions.

Proposed Solution:

CLR 4.0 featureInformation required to call into COM objects is embedded into the assembly itself.Runtime dependency on Interop Assemblies can be pre-compiled and Linked.

We can embed the type of Interop that we use in the code into the assembly. So we don’t need to include the entire dlls. In other word, the new CLR 4.0 enable developers to embed interop assembles(and it just takes the functions/interfaces that are being used by the code) into the assemblies compilation.